DE2827976A1 - CONTROL DEVICE FOR AN AIR CONDITIONING SYSTEM - Google Patents

Description

Patent attorney DIPL.-PHYS. DR. W. LANGHOFF Attorney B. LANGHOFF *

MUNICH 81 ■ WISSMANNSTRASSE 14 · TELEPHONE 93 27 74 · TELEGRAMi 1A, i. \ ■ - ■. [- | , '. i-ioi-li H "f (-Λ ι in I Hl U'.! Ii ft

Munich, June 26th, 1978 Our reference: 71-1743

Patent application
the

BARBER-COLMAN COMPANY, 1300 Rock Street, Rockford, 111.61101

United States

Control device for an air conditioning system

809883/0814

* Permanent general representative according to § 46 PatAnwO. admitted to the regional courts of Munich I and II.

The invention relates to a device for regulating the flow strengths of a conditioned main air flow with superatmospheric pressure and a secondary air flow, with a suction mixing chamber having a first inlet for the Main air flow, a second inlet for the secondary air flow and an outlet for the mixed air flow from the two Has mixed air.

When air conditioning a room, especially cooling, it is desirable to discharge the air at a temperature that is not uncomfortable for accidentally in the flow path of the Airborne people. On the other hand, however, it is desirable to keep the air in an extreme temperature to keep the size of supply lines and other equipment as small as possible. To this end Intake mixing chambers were provided. A main stream of air with a relatively low constant temperature is narrowed through Lines led into a suction mixing chamber, where the flow of this main air is used to create a secondary air flow suck in. This secondary air is usually return air from the room, so it usually has a temperature equal to about who owns the one in the regulated space. By properly dimensioning the main and secondary air flows into the intake mixing chamber if the temperature of the resulting mixed air is below the desired room temperature, it is but not uncomfortable for people in the air stream. Since the main air flow brings the desired cooling, the flow rate of the main air flow must be regulated in order to keep the air-conditioned room practically at the desired setpoint temperature to keep. If the flow strength of the secondary air flow is reversed to the flow strength of the main air flow regulated, the flow strength of the regulated The mixed air given off in the room is kept essentially constant,

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so that the air circulation in the room is essentially unchanged remains regardless of the cooling requirements. Such suction mixing chambers are in US Patents 3,114,505, 26,690, 3,351,157 and 3,583,447.

In all of the cited patents, a damping device is used to maintain a constant static pressure in the direction of flow in front of a main damping regulator for the main flow maintain, which then delivers a desired flow strength of the main air, whereby the size of the cooling effect is regulated, while a second air damping device determines the flow strength of the secondary air to a substantially Maintain constant mixed air flow in the controlled space.

US Pat. No. 3,809,314 discloses a resettable damping device for a constant amount of air.

The invention is based on the object of creating a device of the type mentioned at the beginning, which has an optimal control behavior has while avoiding excessive flow strengths of the mixed air.

Based on the device mentioned above, the provided The object is achieved by a suction device for drawing in secondary air into the mixing chamber as a function of the Flow strength of the main air flow through a first damping device for adjusting the flow strength of the into the mixing chamber incoming main air flow, through a second damping device to adjust the flow strength of the secondary air flow, by an actuating device for adjusting the first damping device, and by this actuating device controlling flow meter for the main air flow to maintain a constant flow rate of the same.

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The invention is additionally described below with reference to schematic drawings using an exemplary embodiment. It demonstrate:

1 is a flow chart illustrating the method used in accordance with the invention;

FIG. 2 shows a sectional view through the mixing chamber, and FIG. 3 shows a schematic view, partly in section, the preferred embodiment of the invention.

The flow diagram shown in Fig. 1 illustrates how pressurized main conditioned air is fed into a suction mixing chamber where the main air flow sucks a secondary air flow into the mixing chamber and like main and secondary air flow mixed with each other and fed into a state-controlled room. This is state of the art. The new is that the flow rate of the in the mixing chamber arriving main air flow measured and the flow with a substantially constant predetermined amount as a function it is regulated by the measured flow that the condition in the space is measured that the predetermined amount as a function of the state measured in the room and the secondary air flow entering the mixing chamber as another Function of the 'measured state is throttled.

It is assumed that the main air is cooled and that the secondary air is return air from a temperature-controlled room. The flow meter controls a flow control device, to maintain a substantially constant flow rate of the main air entering the mixing chamber. This Regulated main air flow sucks in an essentially constant amount of a secondary air flow reaching the mixing chamber. This secondary air has a higher temperature than the main air, mixes with it and forms a mixed air with one

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Between temperature released into the conditioning room will. Since the intermediate temperature of the mixed air is below room temperature, the mixed air lowers the room temperature. If the room is originally hot, maximum cooling is required in order to reach room temperature as quickly as possible lower to a desired temperature. To this end, the main air flow is essentially at a predetermined maximum held constant while the secondary air flow is throttled. If the temperature in the measured room falls below one predetermined value, the flow strength of the main air flow decreased as a direct function of the measured function. At the same time, the flow strength of the secondary air increases as an inverse function of the measured temperature, a substantially constant flow rate of the entering the room Maintain mixed air. This continues until the flow strength of the main air is just sufficient to to deliver the heat loss in the room to the setpoint temperature. If the room temperature falls below the setpoint, then the flow strength of the main air is further reduced as a function of the measured temperature. The cooling is consequently on one is reduced to a lower value than is necessary to compensate for the heat loss, whereby the room temperature rises again. Generally speaking, the flow strength of the conditioned main air is modulated as a function of the measured state in a conditioned space to create and maintain a predetermined state in the space while the flow rate of the secondary air in another state is modulated to a substantially constant flow rate to maintain the mixed air entering the room in order to produce a substantially uniform state there. Since the secondary air flow is sucked in by the main air flow, a main air flow of at least a predetermined amount becomes Maintained at all times to ensure air circulation in the controlled space.

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Fig. 2 shows a mixing chamber 1O with an inlet 11 for conditioned Main air 12, which is supplied with superatmospheric pressure from a main source, not shown, with an inlet 13 for secondary air (generally return air) 14 into the chamber, with an outlet 15 gum blowing out the mixed air stream 16 from main and secondary air from the chamber into a conditioned room, not shown, and with a device 17 in the chamber for sucking in the secondary air flow into the chamber as a function of the main air flow flowing through the chamber, with main and secondary air as the result this suction are mixed together. A first damping device which can be set by an actuating device 21 20 regulates the flow rate of the main air 12 flowing in through inlet 11. One by means of an actuating device 23 adjustable second damping device 22 throttles the flow of secondary air 14 flowing in through inlet 13. This device is known.

The present invention relates to a device for regulating of the actuating devices 21 and 23 in order to reduce the proportion of main and secondary air 12 and 14 in the mixed air flow 16, which in properly proportioning the conditioned space being given off. As can be seen from Fig. 2, a flow meter 30 connections 31 and 32, which are upstream or downstream of an orifice 33 which is in the path of the main air 12 entering through inlet 11. To route compressed air from the connections 31 and 32 lines 34 and 35 are provided.

Fig. 3 shows a flow converter 40 which has a high pressure chamber 41 and a low-pressure chamber 42, between which a flexible membrane 43 forms a common wall. One Rod 44 transmits the movement of the diaphragm to the outside of the flow converter 40. The upper port 31 transmits the

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Pressure via a line 34 to the high pressure chamber 41, and the lower terminal 32 transmits the pressure through a line 35 to the Niederdruckkairaner 42, so that the flow transducer 40 measures the pressure difference, and the rod 44 is adjusted accordingly. The rod 44 engages a rigid flap 45 which is articulated at the end point 46 and has a free end 47.

Pressure-regulated air from a main air source passes through a throttle 51 into a state converter 50 and forms one State-dependent partial air flow, which is regulated by venting via a nozzle 52 according to the position of a State sensor 53. This state sensor responds to a state that is being regulated in the state-controlled room target. As can be seen from Fig. 3, the state sensor consists of a bimetallic spring clamped on one side, each of which can be moved toward or away from the nozzle 52 according to the temperature. Thus, the in the condition sensor 50 generated air pressure depending on the state and forms a state signal. This reaches a pressure chamber 61 of an actuating device 60 as control pressure. One wall of the pressure chamber 61 forms a flexible membrane 62. The force generated on the membrane by the air pressure is controlled by a guide pin 63 transmitted and counteracts the force exerted by a biasing spring 64 on one end of a pivot point 66 rotatable lever 65 is exerted. At the other end of the lever, an adjustable stop 67 is provided which can come into contact with a resilient lever 68 clamped in on one side, in order to achieve a state-variable biasing force to transmit on the flap 45 opposite to the control pressure force, via the lever 68 is a predetermined minimum Pre-tensioning force applied to the flap 45 by the adjusting screw 69 for the minimum pre-tensioning. In the absence of a status signal determines the minimum bias together with the flow signal the position of the end 47 of the flap 45. exceeds the condition-dependent preload the minimum preload

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tion, the position of the end 47 is measured as the puncture of the Status deferred.

The actuating device 21 has a pressure chamber 71, the wall of which is a flexible membrane 72. A guide rod 73 movable through the membrane 72 engages an actuating lever 74. A biasing spring 75 counteracts the outward movement of the rod. The pressure chamber 71 receives air
Via a throttle 76 from a pressure-regulated main air source and blows air out again through a nozzle 77 in accordance with the position of the free end 47 of the flap 45
At the end in the direction of the nozzle 77, the pressure in the chamber 71 increases, and the force resulting therefrom, which acts on the membrane 72, is transmitted via the rod 73 and moves the actuating lever 74 upwards against the force of the spring 75. As can be seen from Fig. 2, the lever 74 is means
a connecting rod 78 operatively connected to the first damper so that upward movement of the lever 74 moves the first damper 20 to the closed position. If the pressure in the pressure chamber 71 decreases, the spring 75 moves the actuating lever 74 downward, so that the
first damping device 20 is opened further.

The actuating device 23 has a pressure chamber 81, one wall of which is a flexible membrane 82. A guide rod 83 that can be moved through the membrane 82 engages an actuating lever 84. A bias spring 85 opposes the outward movement of the rod. The pressure chamber 81 receives this
State signal as air pressure from the state converter 50. If the pressure in the chamber 81 increases, the force resulting therefrom, which acts on the diaphragm 72, is transmitted via the rod 83 against the force of the spring 85 and moves the actuating lever 84 upwards. As can be seen from Fig. 2, is
the lever 84 by means of a connecting rod 86 with the second

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Damping sex device connected so that an upward movement of the lever 84, the second damping device 22 in the closed Position moved. If the pressure in the pressure chamber 81 decreases, the spring 85 moves the actuating lever 84 down, so that the second damping device is opened further.

It is assumed that the condition-controlled room is cooling required to maintain a substantially uniform temperature there. The main air is on one essentially constant cool temperature, around 278 K, chilled. At the beginning, the flap 45 is set by the lever 68 so that that the end 47 is at a distance from the nozzle 77, so that branch air is blown out of it and the pressure in the pressure chamber 71 is lowered. As a result, the spring 75 moves the operating lever 74 downward to ensure that the first Damping device 20 is open. Thus, the pressurized cold main air flow through the inlet 11 into the Flow into the mixing chamber 10 and through the outlet 15 into the temperature-controlled Room. If the state sensor 53 measures a relatively high temperature in the room, the Nozzle 52 is essentially closed, giving rise to a relatively high condition signal in the form of high air pressure causes to the actuating device 23 and the adjusting device 60. High pressure in the pressure chamber 81 moves the operating lever 84 upwards in order to close the second damping device 22 and thereby the inflow of the secondary air flow 14, which should be the return air flowing into the mixing chamber with the measured room temperature. The result of this is a maximum of cooling, so that the temperature-controlled room cools down quickly, without possibly being in the Stream of the supplied cold air to be annoying to people. The high pressure in the pressure chamber 61 moves the lever 65 such that the adjustable stop 67 engages the lever 68, which then the free end 47 of the flap 45 of

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the nozzle 77 is moved away, whereby the pressure in the pressure chamber is lowered. As a result, the lever 74 is actuated by the spring 75 moved downwards, the first damper is opened wide, and consequently a large cold main air flow 12 flow through the mixing chamber 10 and are released into the temperature-controlled room.

The flow of the main air 12 through the throttle orifice 33 creates a lower pressure on its underside. The higher pressure Above the throttle at the connection 31 is via the line 34 into the high pressure chamber 41 in the flow converter 40, while the lower pressure below the throttle orifice at the connection 32 via the line 35 into the high pressure chamber 42 is directed. If the flow strength of the main air flow at the throttle orifice 33 increases, for example due to an increase in pressure at the primary source or a decrease in the main air required to condition others from the same Source of supplied rooms, then the difference between the upper and lower pressures increases. This practices the flexible membrane 43 exerts a greater downward force on the flap 45 via the rod 44, namely in the opposite direction to the biasing force provided by lever 68. As a result of this, the free end 47 approaches the nozzle, restricts the flow of air through the latter, increases the air pressure in the pressure chamber 71 and causes the operating lever to move upwards and the first damping device 20 partially closes, whereby the flow strength of the main air flow is reduced in the mixing chamber. If the main airflow decreases, the difference between the upper and lower also decreases Pressure from, and the first damping device 20 is opened even further. As a result of opening and closing the The damping device corresponding to the flow-dependent pressure differences from the flow converter 40 is the flow strength of the main air flow entering the mixing chamber kept practically constant.

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If the measured temperature falls in the controlled room, moves the condition sensor 53 moves away from the nozzle 52 so that more air can pass through it and the air pressure is reduced, which is output as a status signal by the status converter 50 to the pressure chambers 61, 81. Because of the low Pressure in the pressure chamber 61, the spring 64 moves the lever 65, which then moves the adjustable stop 67 downwards and thus the biasing force applied by lever 68 to flap 45 is reduced. The flap 45 moves down, so that its free end 47 approaches the nozzle 77, whereby the air flow through the latter continues to be restricted and the air pressure in the pressure chamber increases. This increased pressure exerts an increased upward force on the actuating lever 74 off, which leads to a partial closing of the first damping device and a reduction in the flow rate of the main air flow entering the mixing chamber. This decrease is not the result of an increase in the measured flow rate, but rather a readjustment the value at which the flow strength at reduced Cooling demand is to be maintained. The lower pressure in the pressure chamber 81 causes the spring 85 to move the operating lever 84 pushes down. This causes the second damping device 22 to partially open, so that secondary air 14 can enter which should again be the return air with the measured temperature of the condition-controlled room. The one through the suction device 17 reaching the mixing chamber 10 main air flow 12 sucks secondary air 14 into the air flow, which the mixed air 16 results, which through the outlet 15 in the condition-controlled Space exits. The position of the second damping device 22 is regulated as a function of the measured state in the condition controlled Room regulated in such a way that the flow strength of the mixed air flow remains essentially uniform. With In other words, the flow rate of the main air increases accordingly a decrease in the state signal decreases, the flow rate of the secondary air decreases by substantially the same Amount to. A change in the status signal therefore has an opposite effect on the flow strengths of the main and secondary air

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Effect. Takes the measured state up to the desired one Setpoint, the proportion of secondary air in relation to the Main air increased until the. into the room when the setpoint state is reached, it is equal to the loss this is. Further changes in the measured state result in a modulation of the air that is regulated as misal air Main and secondary air components emitted from the room, as required is to keep the measured state constant at the target value. Although the temperature of the mixed air is up changes with the proportions of main and secondary air mixed therein, the flow strength of the mixed air remains essentially constant so that the air distribution pattern in the room remains unchanged.

The invention is not limited to that shown and described Embodiment limited; Rather, changes and additions can be made without affecting the actual Invention idea is deviated. For example, the working methods of various components can be reversed will. Instead of the pneumatic and mechanical components described, electrical, electronic and mechanical components are used.

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Claims (13)

71-1743 - Y - Patent claims: Device for regulating the flow strengths of a conditioned main air flow with superatmospheric pressure and a secondary air flow, with a suction mixing chamber, a first inlet for the main air flow, a second inlet for the secondary air flow and an outlet for the mixed air mixed from the two air streams, characterized by a suction device (17) for sucking in secondary air (14) into the Mixing chamber (10) depending on the flow strength of the main air flow (12), through a first damping device (20) to adjust the flow rate of the in the main air flow entering the mixing chamber, through a second damping device (22) for adjusting the Flow strength of the secondary air flow through an actuating device (21) for adjusting the first damping device (20), and by means of this actuating device (21) controlling flow meter (30) for the main air flow to maintain a constant flow strength same. 2. Apparatus according to claim 1, characterized by a sensor for a state variable that is to be regulated in the room and by connecting the sensor to the actuating device (21) for the main air flow. 3. Apparatus according to claim 2, characterized by a connection of the sensor to the second Damping device (22) and by such a design of the connection that the flow strength of the from the Main air flow and the secondary air flow formed mixed air is kept constant. 809883/0814 ORIGINAL INSPECTED 2827376 4. Apparatus according to claim 2 or 3, characterized in that the sensor is a flow meter (30) and a flow converter (40), which corresponds to the measured flow strength of the main air flow Control signal for the actuating device (21) generated. 5. Apparatus according to claim 2 to 4, characterized in that the sensor has a throttle point (33) in the main air flow channel and two lines (34,35) arranged on both sides of the same, the lead to the flow converter (40) and that the flow converter (40) forms a double-chamber pressure cell whose both chambers (41,42) are on both sides of a flexible membrane (43) that the two lines (34,35) to each one of the two chambers are connected, and that the deflection of the flexible membrane (43) by a transmission member (44) is transmitted as a control signal to the outside of the pressure transducer (40). 6. Apparatus according to claim 1 to 5, characterized in that the actuating device (21) a pressure chamber (71) with a flexible membrane (72) comprises that the pressure chamber of the pressure cell (71) via a Throttle (76) is connected to a regulated compressed air source and also to an outlet nozzle (77) whose The outflow resistance can be changed by the control signal of the pressure transducer. 7. Apparatus according to claim 6, characterized in that the actuating device (21) is one of the Pressure cell (71) counteracting biasing spring (75) and an actuator (74) acted upon by both, the the first damping device (20) adjusted. 809883/0814 2B27976 8. Apparatus according to claim 6 or 7, characterized in that the discharge resistance of the discharge nozzle (77) comprises a flap (45) whose distance from the opening of the discharge nozzle (.77.) Can be changed, and that on this flap the control signal of the pressure transducer and a pretensioning device acting in the opposite direction Attack (68). 9. Apparatus according to claim 8, characterized in that g e k e η η, that the pretensioning device (68) with an adjusting device for adjusting a minimum Pretensioning force is provided. 10. Apparatus according to claim 8 or 9, characterized in that the pretensioning device is variable is designed to change the prestressing force as a function of the state variable in the controlled space. 11. The device according to claim 1O ₇ characterized in that the pretensioning device comprises a pressure cell, the pressure chamber (61) of which is connected to a pneumatic state converter (5-0) for converting the state variable to be controlled into a pressure control signal, and that the pressure cell is under the biasing action of a biasing spring (64) counteracting it. 12. The device according to claim 11 and 1 to 10, characterized characterized in that a second actuator (23) is provided for adjusting the secondary air flow and that this actuator of the State converter (50) is controlled. 13. The device according to claim 12, characterized in that g e k e η η that the second actuator (23) has the same structure as the actuating device (21) 809883 / 08U